This invention relates to an apparatus and a method for recording moving pictures and still pictures using a general-purpose standard for encoding moving pictures, such as MPEG2, and a recording medium having moving and still pictures recorded thereon.
In Japanese Laying-Open patent Publication 3-34686, there is disclosed a digital still picture signal recording/reproducing device in which, as moving picture signals are recorded, desired still picture signals are selected from video camera output signals and recorded in a digital memory, such as RAM, and in which signals sequentially read out from the digital memory are divided into plural tracks for recording on a digital speech recording/reproducing device.
In the digital still picture signal recording/reproducing device, the digitally-recorded still picture signals are recorded along with identification signals specifying that the digitized still picture signals are signals other than speech signals, for demarcating the digitally-recorded still picture signals from the digital speech signals.
In the Japanese Laying-Open Patent publication 5-36205, there is disclosed a magnetic recording device in which moving pictures can be imaged even during timer operation on the occasion of imaging a still picture using a timer.
In the Japanese Laying-Open Patent publication 5-115053, there is disclosed a magnetic recording device in which a specified one of contiguous analog moving pictures is recorded as still picture signals in a still picture recording area and the still picture is also continuously recorded in the moving picture recording area for enabling comprehension of the contents of the recorded still picture at the time of reproduction of the moving picture.
In the Japanese Laying-Open Patent publication 7-193777, there is disclosed a video camera capable of simultaneously recording the moving picture and the still picture in which, if recording release mode is selected during recording of the still picture signals, the recording picture release mode is executed after completely recording the still picture signals for not allowing incomplete still picture to be left.
Meanwhile, in a conventional device for recording both the moving and the still picture, the moving picturers are recorded as analog signals on a magnetic tape, whilst the still picture is recorded as PCMed digital signals in a digital signal recording area. Thus, two channels of the signal processing circuits, namely an analog signal processing circuit for recording moving pictures and a digital signal processing circuit for recording still pictures, are required, thus complicating the device structure. For reproducing the recorded moving and still pictures, two reproducing circuits for coping with the two recording systems are required.
If a still picture is imaged during recording the moving pictures, the same scene is recorded in duplicates by analog and digital signals. If only a still picture is recorded, an analog signal recording area for a moving picture is not used. In such case, the recording capacity of the recording medium, such as a magnetic tape, is not utilized effectively.
Moreover, if a still picture is imaged during recording of moving pictures, the digital signals of the imaged still picture are recorded in the speech signal recording area, so that, during recording of digital signals of the still picture, speech recording is interrupted.
Thus it may be contemplated to record on the recording medium the moving picture and the still picture by the compression system for moving pictures and by the compression system for still pictures, respectively using such as MPEG standard, in order to make common use of the recording device for recording the moving picture and for recording the moving picture for enabling effective utilization of the recording capacity of the recording medium as well as preventing interruption of speech recording.
However, with the structure of simply recording compressed data for moving pictures and that for still pictures, it becomes difficult to selectively record only still pictures.
For overcoming the above drawback, it is an object of the present invention to provide a still/moving picture recording apparatus and a still/moving picture recording method in which a common hardware structure is used for recording moving pictures and still pictures and in which effective utilization can be made of the recording capacity of the recording medium even in case moving pictures are recorded together with a still picture, and a recording medium for still and moving pictures having recorded thereon the moving pictures together with still pictures.
It is another object of the present invention to provide an apparatus and a method and a recording medium for moving/still pictures for enabling only the still picture data to be selected and reproduced.
The still/moving picture recording apparatus according to the present invention includes picture compressing means for compressing input picture signals for conversion to picture data, recording means for recording the picture data outputted by the picture compressing means on a recording medium and picture compression system switching means for switching the picture compression parameters of the picture compression means between those for moving picture recording and those for still picture recording for switching the picture compression system. With the above picture compression system switching means, the compression system is preferably switched for still picture recording to an intra-frame encoding (I-picture) or to forward predictive encoding (P-picture). Also, with the still/moving picture recording apparatus according to the present invention, the picture compression system is automatically switched between that for moving picture recording and that for still picture recording for recording compressed picture data on the recording medium.
The still/moving picture recording apparatus according to the present invention includes picture compression means for generating, for the moving picture recording mode, picture data compressed based on the compression parameters for moving picture recording, and for generating, for the still picture recording mode, compressed picture data compressed based on compression parameters for still picture recording, and recording means for recording picture data generated by the picture compression means on an exchangeable recording medium. Picture data inclusive of the still picture recording mode information specifying that the picture is a still picture is recorded on the recording medium for the still picture recording mode. The still picture recording mode information specifying that the picture recorded is the still picture may be such information in which the quantization coefficient of the first macro-block of picture data compression-encoded in accordance with the MPEG standard is fixed at a specified value. The compression parameters for still picture are set in meeting with for example the magnitude of the motion vector or the input picture position.
In the still/moving picture recording method wherein picture compression parameters are switched between those for moving picture recording and those for still picture recording, input picture signals are converted into compressed picture data by a picture compression system different between one for moving picture recording and one for still picture recording, and the compressed picture data is recorded on a recording medium. With the still/moving recording method, the picture compression system is switched during still picture recording to intra-picture encoding or to forward predictive encoding for converting the input picture signals to compressed picture data which is recorded on the recording medium.
In the still picture recording method according to the present invention, picture data compressed based on compression parameters for moving picture recording is generated for a moving picture recording mode for recording on a recording medium and picture data compressed based on compression parameters for still picture recording is generated for a still picture recording mode for recording on the recording medium along with the still picture recording mode information specifying that the picture recorded in a still picture. With the present still/moving picture recording method, the compression parameters for still picture provide that, in compression encoding by MPEG as a standard for encoding, the quantization coefficient of the initial macro-block of picture data be fixed at a pre-set specified value, and the information in which the quantization coefficient of the initial macro-block of picture data is fixed at a pre-set specified value is used as the still picture recording mode information. The compression parameters for still picture are set in meeting with for example the magnitude of the motion vector or the input picture position.
The still/moving picture recording medium according to the present invention has a moving picture recording area and a still picture recording area having recorded therein compressed picture data obtained by switching the picture compression parameters for converting input picture signals by picture compression systems different for moving picture recording and for still picture recording.
The still/moving picture recording medium according to the present invention has a moving picture recording area and a still picture recording area. The moving picture recording area has recorded therein picture data compressed based on compression parameters for moving picture recording while the still picture recording area has recorded therein picture data compressed based on compression parameters for still picture recording as well as the still picture recording mode information specifying that the picture data recorded is a still picture.